If you find it unlucky that there are 13 Courts of Appeals in the federal judicial system, think of them as 12 geographically-based Circuit Courts of Appeals plus one other, the Court of Appeals for the Federal Circuit. Taken together, they represent the first level of appeal from federal trial court decisions. The second and top level of appeal is the highest court in the land, the United States Supreme Court.
TL;DR (Too Long; Didn't Read)
The federal judiciary has 12 regional Courts of Appeals and one more for the federal circuit, for a total of 13 Courts of Appeals.
What Are the U.S. Courts of Appeals?
Every state in the land has a similar court system, with trial courts on the lower levels, appellate courts on the middle rung and a high court on the top of the pyramid. The federal judiciary is configured in the same pyramid shape.
The federal system divides the nation into 94 geographical districts, then groups these into 12 circuits. Each circuit has its own circuit court. The trial courts are termed Federal District Courts and are the first courts to hear a particular case. Once a decision has been rendered in a District Court, it can be appealed to the circuit court for that district. Circuit courts are also called U.S. Courts of Appeals.
The 13th Court of Appeals is called the Court of Appeals for the Federal Circuit. It hears cases from around the entire nation on very specific issues such as patents.
What Types of Cases Do the Courts of Appeals Hear?
Appeals to the Courts of Appeals are said to be "of right." That means that any losing party in a district court case has the right to bring an appeal to the appropriate Court of Appeals that serves the district. District courts hear cases involving federal law or cases in which the parties are in different states.
This is different than the second level of federal appeals, which is the U.S. Supreme Court. Appeals to the U.S. Supreme Court are not "of right," but by selection. Parties wishing to appeal to the Supreme Court must file a petition asking for the appeal to be heard. Of the some 7,000 requests for review every year, the Supreme Court accepts only 150 or less.
This makes the decisions of the Courts of Appeals very important. In cases other than the small percentage accepted by the U.S. Supreme Court for review, decisions of these courts stand as the final word on the relevant federal law.
How Many Courts of Appeals Are in Each State?
Remember that the federal system divides the country geographically into districts, then groups the districts into circuits. Each circuit has one Court of Appeals. These are called the Court of Appeals for the First Circuit, Second Circuit, etc. Since there are only 12 circuits, there are only 12 Courts of Appeals that are linked geographically to the states. Given the fact of 50 states, it is clear that no state has more than one Court of Appeals and that many states must share a Court of Appeals with other states.
For example, the U.S. Circuit Court of Appeals for the Fifth Circuit includes the states of Texas, Louisiana and Mississippi. All district court case appeals from those states are heard in that Court of Appeals.